Crane-brake.



L H. LINDSEY. CRANE BRAKE. APPLICATION FILED D110. 30, 1912.

2 SHEETS-SHEET 11 Patented Feb.. 16, 19 1 L. H. LINDSEY.

CRANE BRAKE. I APPLIOATIOIT FILED DIE (L 80,1918. I

PatentedFeb. 16, 1915.

-certa1n friction elements.

LEWIS n. LINDSEY, OEBIRMlNGI-IAM, ALABAMA.

CRANE-BRAKE.

Specification of Letters Patent. Patented Feb 1'6 1915 Application filedDecember 30. 1912. Serial No. 739,257.

To all whom it may concern:

Be it known'that I, LEWIS H. LIxDsEY, a citizen of the United States,and resident of Birmingham, in the county of J eifer son and State ofAlabama, have. invented certain new and useful Improvements in CraneBrakes, of which the following is a specifi My invention relates tohoisting devices and has particular reference to a novel brake for useon cranes.

In the use of cranes for the purpose of conveying materials, when theload is lowcred the released weight cannot be allowed to drop, neithercan its descent be advantageously controlled by the crane motor. It istherefore customary to employ an auto matic brake controllable by theoperator by means of which the load may be lowered gradually under thebraking influence of A disadvantage in such de ices heretofore proposedis that the holding device, usually a toothed wheel and pawl, whileproviding suflicient strength under ordinary circumstances is frequentlybroken due to a sudden shock. The uncontrolled descent of a load such asa ladle containing fluid metal frequently results disastrously and it isan. object of the present invention to provide a brake ap plicable tothe crane cable drum which shall provide maximum engaging surfaces thusobviating the danger of breakage under a sudden shock.

A further object is the elimination in such a device of the usual pawl,the action of which is uncertain and which is easily.

broken.

In my device I contemplate the employ-' ment of the usual shaft having apair of friction. disks, one rotatable with the shaft and other arrangedfor limited rotation by ramps of screw threaded engagement whereby thebraking action of the disks may be controlled, a large gear looselymounted on the shaft and providing a bearing surface for the disks, anda pinion constantly ongiging the large gear and adapted for bodilymovement toward and away from a plurality of rigid projections or teethsecured to the casing. The action of the pinion is automatic; itsmovementin either di rectior toward or away from the engaging stop iscontrolled by the direction of movement of the large gear, as forinstance, when the load is being lifted the,.la;;ge gear will circle.

revolve in a direction tending to move the pinion .out of engagementwith the stops. In such case the brakes will have no infl'u once-theshaft rotating freely in the casing. Howeyer, on the lowering movementthe gear tends to revolve inthe opposite direct1on,thus carrying thepinion into engagefment with'the stops and preveilting the furtherrotation'of the gear. Thus any movement of the shaft must'beafterovercoming the frictional resistance exerted by the two disks. I

The invention will be more readily understood by reference to thedrawings, in which,

Figure l is ase'ction, on the line 1-'1' of Fig. 2 Fig.2 is a section ontheline 22 of -Fig. 1i1 showing the pinion in engagement gaged from thestops; Fig. 4 is an end ele- .vation of the pinion and shaft; Fig. 5 isan end elevation of the bearing provided in the casing for the pinionshaft; Fig. 6 isfa face view of one of the friction disks; Fig; 7 is asimilar view of. the other friction disk,

and FigsJS and 9 are side elevations of the disks shown in Figs. 6 and 7respectively."

. Referring more particularly to the drawmgs, 1t Wlll be seenthat ashaft 10, suitably connected to. the cable drum. is mounted in a casingformed of lower and upper portions ing suitably mounted on a rlgidportion of the crane. The shaft does-not bear directly on the"cas1ng butisxmounted within disks 13, 14. These disks are provided with longsleeves 15, 16 respectively, within which the 11, 12,.the lower portionofthe casing beshaft is accommodated. I The disk 14 is suitably keyed tothe shaft out is adapted for longitudinal adjustment thereon by means ofa nut 17 threaded on the shaft. The shaft is provided with a plurality.of screw threads 18 and the sleeve 1501? the disk 1.3

is interiorly threaded, and engages therewith. The outer end of thesleeve 15 is-recessed to form teeth 19, adapted to be engaged bysuitable gears, by means of which the disk may be rotated to a certaindegree on the shaft whereby the frictional effort ios exerted may becontrolled by the operator.

of movement permitted by the disk 18 on its screw threads. of the disks,one of which is keyed to the shaft, also requires the rotation of bothdisks with the shaft under all circumstances. A large gear 22' ismounted be tween the two disks 13, 14, a bearing being provided on awearing plate 23. This wearing plate is seated against the face of thedisk 13 and has a concentricprojecting flange 24, fitting the concentriccircular opening in the gear 22 and bearing on the two arc-shapedprojections 20, 21 on, the faces of the disks. gear 22 and the face ofthe friction disk 14 I provide a plate'of suitable friction material 25.

WVith the mechanism thus far described there will be no braking actioninasmuch as the friction disks would not operate without a stop for thegear. Such'stop is pro vided in the pinion 26, rotatably mounted on theshaft 27, which shaft has squared or flattened ends 28, which ends areseated in the slots 29, in the bearing plates 30, suitably secured tothe top portion 12 of the casing and covering apertures 31 therein,these apertures being of a size to permit the insertion and removal ofthe pinion 26.- The pinion is centered on the shaft 27 and a slightfriction resistance provided by means of plates 32, pressed against thepinion by means'of right and left hand coil springs 33, the compressionof the springs being controlled by the nuts 34: screw-threaded on theshaft. It will be noted that-the slots 29, within which the ends of theshaft 27 are seated are inclined, the center line of which is formedfrom an arc struck from the cen ter of the shaft 10. The stop for thepinion 26 is ablock 35 of considerable size and strength rigidly securedto the upper portion 12 of the casing and provided on one face with aplurality of teeth 36, These teeth arestrong and provide a comparativelylarge area of engagement with the teeth of the pinion obviating anypossibility of breakage due to sudden shocks. It will be noted that thetendency, of the pinion and its shaft will be to follow the periphery ofthe large gear 2-9, or perhaps, more correctly speaking, to move withthe gear at a tangent. However; as tangential movement is not permitted,the pinion and its shaft This inter-engagement Between the web. of thewill move under the rotative influence of the large gear to the extentpermitted by the slot. This action is augmented by the frictionalresistance against rotation of the pinionwith relation to the shaft. Itwill be seen that the greater. the resistance of the pinion is of commoncommercial construc- 'tion and need not be, as in the case of many ofthe devices at present in use, of special construction adapted tocooperate with a pawl or series of pawls. This fact takenin connectionwith the ready removability of the pinion through the opening 31in thesides of the casing, provides means for ready inspection or repair.

It is obvious that modifications might be made in the exact constructionshown sytch as in the location of the pinion with relation to the gearcasing and in other features all without departing from the spirit of myinvention.

I claim:

1. In a crane brake, the combination of a casing having slots, a brakegear mounted -1n said casing, a pinion constantly engaging said gear, ashaft on which said pinion is mounted the ends of said shaft beingcarried 1n slots in said casing, said shaft being prevented fromrotation within said slots,

constant engagement with said gear, frictinn means between said pinionshaft and pinion, and a stop secured to said casing and arranged to beengaged by said pinion under the influence of said gear, substantiallyas described.

LENIS H. LINDSEY. \Vitnesses (1C. BURKE,

E. Pr'r'r.

